It would appear that Safari will no longer be offered for Windows. Or, at least that is the thought after doing a bit of searching around Apple's site. It would seem that the link to Safari for Windows has been removed from the main download page. OSX Mountain Lion ushered in Safari 6 with it, and there is certainly no easily visible link.
Safari 5.1.7 was located on Apple's knowledge base, but that's the only link that could be found. A search for a Windows version of Safari still brings up a link to "Safari for Mac + PC," but clicking that page takes users tot he main Safari page where there seemingly is no download link in site.
Offered since June 2007, usage numbers on the browser have it accounting for about 5% of total internet traffic. Most of that traffic is likely coming from Mac OSX so a quiet death for the browser isn't too unbelievable. It certainly could be a mistake, but that seems highly unlikely given Apple's track record.